A gas discharge lamp is a well-known light source that typically consists of a glass envelope containing a low-pressure gas such as argon, krypton, neon, or a mix of these gases, and a quantity of an ionizable material such as mercury.
The lamp emits light by creating an electric arc passing through the gas. The arc is created by applying a large Alternating Current (AC) voltage across the cathodes of the lamp.
A fluorescent lamp is a well-known type of gas discharge lamp. A typical fluorescent lamp consists of an elongate gas envelope having an interior wall coated with a suitable phosphor, and having a cathode at each end of the envelope for application of an AC voltage across the lamp.
In operation, the gas discharge lamp appears as a negative impedance device; that is, the voltage drop across a gas discharge lamp will tend to decrease with increasing discharge current. Thus, a high voltage is required to create or strike the arc through the lamp followed by a lower voltage to maintain the arc once the arc is struck.
A ballast circuit is normally used to provide a high starting voltage and to provide a positive series impedance for other current limiting mechanisms to maintain the arc voltage once the lamp is struck. In a typical ballast circuit, the ballasting function is generally provided by an inductor connected in series with the gas discharge lamp. A gas discharge lamp has a natural frequency; that is the lowest frequency at which the gas discharge lamp will resonate without the addition of any external inductance or capacitance.
The purpose of the foregoing Abstract is to enable the public, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection, the nature and essence of the technical disclosure of the application. The Abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
Still other features and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description describing only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiment are to be regarded as illustrative in nature, and not as restrictive in nature.